Peptide Hormones

Question 1

How are peptide hormones transported throughout the body

Answer 1

through the circulatory system without the need for carriers

Question 2

Why are peptide hormones synthesized as needed

Answer 2

they have very short biological half-lives and are broken down quickly

Question 3

What are prohormones

Answer 3

large polypeptide chains which are modified and cleaved into hormones (sometimes multiple)

Question 4

Why are peptides effective even after travelling through the blood

Answer 4

They can work at low concentrations

Question 5

Peptide hormones are very large so what type of receptors do they typically bind

Answer 5

GPCRs and kinase-linked receptors

Question 6

What causes a protein to take on a ring structure or for two chains to be held together

Answer 6

Disulfide bonds

Question 7

In what form is insulin initially produced

Answer 7

preproinsulin

Question 8

Explain the production of proinsulin

Answer 8

The leader sequence of preproinsulin is cleaved in the ER lumen resulting in proinsulin

Question 9

Explain the production of insulin

Answer 9

Proteases cleave at 2 sites removing the C chain
The A and B chains remain connected by disulfide bonds

Question 10

What determines which hormones will be produced from a prohormone

Answer 10

the expression of the enzymes which cleave prohormones